The state health insurance exchange opening Oct. 1 will be the bold new face of Obama-care, for better or worse.

Better — if it signs up hundreds of thousands of previously uninsured Coloradans to affordable policies; channels federal subsidies to help them pay; and meshes complex computer networks to make it happen.

Worse — if the computers refuse to talk to each other; if it takes hours to explain the very concept of insurance to first-time customers; or if insurers have a bad first year and quickly raise rates.

Exchanges like Connect for Health Colorado are a crucial part of national health-insurance reform, alongside the Medicaid expansion. They're a discount health store of last resort for people who don't qualify for public insurance and couldn't afford previous plans.

The website serves as call center and general navigator, ruled by state appointees and spending federal money. It's where private insurance companies will sell affordable policies, and consumers and small businesses can get subsidies.

At least 10 insurers will compete on the Colorado exchange, with dozens of plan variations, including Kaiser, Anthem and Humana.

Each policy will come at price and benefit levels of "bronze," "silver," "gold" and "platinum" — bronze and silver will be cheaper, but come with higher deductibles and more limited provider networks.

The exchange also is where small businesses can shop for a wider array of policies, and match up with federal tax credits.

The poorest Coloradans usually qualify for Medicaid. Connect for Health Colorado is aimed at people who make between $15,000 and $46,000 a year, couples with income of $20,000 to $62,000, and families of four between about $31,000 and $94,000. Almost half a million Coloradans could qualify.

The government will pay the subsidy directly to the insurer, with the insured person paying the rest. Those with higher incomes can still buy the plans, but they won't get a subsidy.

Enrollment is open Oct. 1 through March 31, with policies and subsidies taking effect Jan. 1. (Medicaid-expansion clients can apply any time after Oct. 1, with no ending point.) To start, go to connectforhealthco.com, or call 1-855-752-6749.

Many local social agencies and nonprofits will have trained people to help in the signup process. Existing insurance brokers also can help, and they will receive a commission from the chosen plan.